
Philips Semiconductors
Preliminary specification
XA-S3
XA 16-bit microcontroller
32K/1K OTP/ROM/ROMless, 8-channel 8-bit A/D, low voltage (2.7 V–5.5 V),
I2C, 2 UARTs, 16 MB address range
2000 Mar 09
32
LSB
MSB
BIT
SYMBOL
FUNCTION
RSTSRC.7
—
Reserved for future use. Should not be set to 1 by user programs.
RSTSRC.6
—
Reserved for future use. Should not be set to 1 by user programs.
RSTSRC.5
—
Reserved for future use. Should not be set to 1 by user programs.
RSTSRC.4
—
Reserved for future use. Should not be set to 1 by user programs.
RSTSRC.3
—
Reserved for future use. Should not be set to 1 by user programs.
RSTSRC.2
R_WD
Indicates that the last reset was caused by a watchdog timer overflow.
RSTSRC.1
R_CMD
Indicates that the last reset was caused by execution of the RESET instruction.
RSTSRC.0
R_EXT
Indicates that the last reset was caused by the external RST input.
—
RSTSRC
Address:463h
Not bit Addressable
Reset Value: see below
—
R_WD
R_CMD R_EXT
SU00942
Figure 24. Reset source register (RSTSRC)
INTERRUPTS
XA-S3 interrupt sources include the following:
External interrupts 0 and 1 (2)
Timer 0, 1, and 2 interrupts (3)
PCA: 1 global and 5 channel interrupts (6)
A/D interrupt (1)
UART 0 transmitter and receiver interrupts (2)
UART 1 transmitter and receiver interrupts (2)
I2C interrupt (1)
Software interrupts (7)
There are a total of 17 hardware interrupt sources, enable bits,
priority bit sets, etc.
The XA-S3 supports a total of 17 maskable event interrupt sources
(for the various XA peripherals), seven software interrupts, 5
exception interrupts (plus reset), and 16 traps. The maskable event
interrupts share a global interrupt disable bit (the EA bit in the IEL
register) and each also has a separate individual interrupt enable bit
(in the IEL or IEH registers). Only three bits of the IPA register
values are used on the XA-S3. Each event interrupt can be set to
occur at one of 8 priority levels via bits in the Interrupt Priority (IP)
registers, IPA0 through IPA5. The value 0 in the IPA field gives the
interrupt priority 0, in effect disabling the interrupt. A value of 1 gives
the interrupt a priority of 9, the value 2 gives priority 10, etc. The
result is the same as if all four bits were used and the top bit set for
all values except 0. Details of the priority scheme may be found in
the
XA User Guide.
The complete interrupt vector list for the XA-S3, including all
4 interrupt types, is shown in the following tables. The tables include
the address of the vector for each interrupt, the related priority
register bits (if any), and the arbitration ranking for that interrupt
source. The arbitration ranking determines the order in which
interrupts are processed if more than one interrupt of the same
priority occurs simultaneously.
EXCEPTION/TRAPS PRECEDENCE
DESCRIPTION
VECTOR ADDRESS
ARBITRATION RANKING
Reset (h/w, watchdog, s/w)
0000–0003
0 (High)
Breakpoint
0004–0007
1
Trace
0008–000B
1
Stack Overflow
000C–000F
1
Divide by 0
0010–0013
1
User RETI
0014–0017
1
TRAP 0–15 (software)
0040–007F
1